Discipline: Chemistry and Chemical Sciences
Subcategory: Chemistry (not Biochemistry)
Hunter Richman - Indiana University South Bend
Co-Author(s): Garrett Taggart, University of Delaware, Newark, DE
Gaseous fuels like methane are a potentially greener alternative to other fuels such as gasoline. However, gaseous fuels have a lower energy density than liquid fuels and thus require more space for the same amount of energy. This means gaseous fuels must be compressed, cooled, or constantly piped in to be a viable fuel source. A possible solution to this is to adsorb gaseous fuels onto substrates with a large surface area. Adsorbing gases to a substrate has the potential to increase the energy density of gaseous fuels allowing them to be a more ubiquitous source of energy. Metal-organic frameworks (MOFs) are one area of said substrates. MOFs have a large surface area, the ability to absorb gas at open metal sites, and various properties depending on the ligands attached to the framework. Post synthetic MOF modification (ligand exchange) is a relatively new area of study. Thus, studying the thermodynamics and kinetics of ligand exchange is a worthwhile and promising area. Specifically, the exchange of the following ligands was investigated: diphenylacetamido-isophthalic acid, isophthalic acid, bromoisopthalic acid, and tert-butylisophthalic acid. Ligand exchange is an equilibrium reaction thus, the extent of the exchange is dependent on the ligand / ligand concentration. Different ratios of MOF to ligand were mixed in solution and the reaction kinetics were measured using UV-Vis. The precipitated cages were analyzed with NMR to find the ligand ratios. These ligand exchange reactions were also run at different temperatures which allowed some thermodynamic data to be gathered. The reaction orders and ligand ratios were found for all the ligand exchange reactions. The approximate activation energy was found for three of the ligand exchange reactions. Future experimentation would include more temperature dependent trials.
Funder Acknowledgement(s): NSF
Faculty Advisor: Garrett Taggart, firstname.lastname@example.org
Role: I performed all of the ligand exchange reactions and UV-Vis. I also did about half of the NMR and data analysis.